Something a bit more advanced: Clearing Map objects without deleting the whole record

User-added image

Something a bit more advanced: Clearing Map objects without deleting the whole record
User-added imageA very useful map editing function is the Clear Map Objects command. For example, there may be instances where we need to re-geocode a set of data. Perhaps the addresses have been improved or updated. The Geocode command in MapInfo Pro does not have an option to overwrite the existing points when geocoding the table again. Therefore, before re-geocoding the table, it is necessary to get rid of the existing points.

Clear Map Objects is a command that deletes the map objects without deleting the attribute data.

In MapInfo Pro 16.0, the command can be found in the Edit group on the TABLE tab.

User-added image

The command can be found in the Edit menu in the 32 bit version of MapInfo Pro. 

User-added image 
Figure 1: Edit -> Clear Map Objects Only.

Using the Clear Map Objects Only menu command

This command is fairly straightforward to use. The requirements are

(1) The layer for which you wish to clear map objects must be editable.
(2) You must select the objects you want clear. (You can select the entire table.) 
(3) Click on Clear Map Objects on the TABLE tab

What if I make a mistake? Undo and Revert table

When you take the steps above, there is no warning. The map objects will be deleted. 

If you have made an error and you notice right away you can try using the Undo command in the Clipboard group on the HOME tab. The Undo command can only undo the single most recent action, also, it is limited in the scope (or size) of what has to be undone. If you deleted a large number of objects the command may not be available. Furthermore, a preference can be found in the System Preferences dialog box (via Options on the Backspace area that you find via the PRO tab) that permits you to control the overall number of objects and maximum memory to reserve for executing an "Undo".

If Undo is not available to you then you can use the Revert Table command in the Content group on the TABLE tab. This restores the table back to its last saved version. This would mean losing multiple changes you have made to the table.

Another way to delete all of the Map Objects in a table

The technique described above can be used on a selection of a few rows or a selection of the entire table. An alternative to getting rid of all of the map objects for an entire table is to use the Table Structure command.

User-added image 

To get rid of all of the map objects in the table uncheck Table is Mappable. This operation is permanent and cannot be undone in any way, once you click OK. You will get this warning before the operation proceeds.

User-added image 

Behind the scenes, this making the table "unmappable" eliminates the files that contain the Map Objects. Merely deleting the objects is slightly different. The table can continue to hold map objects, it is just there are no objects in the table. 

And one final note about Creating Points...

If you use the Create Points capability, you do not need to use the techniques in this article to re-do a create points operation. Within the Create Points dialog box there is an option to overwrite existing points. You would need the techniques in this article if you are going to re-geocode a table.

User-added image
Article by Piyush Trika, Data Dev, Noida

When not writing articles for the MapInfo Pro journal, Piyush loves to explore ways to innovate with diverse geospatial data and its utilization, read lifestyle and health articles/magazines and enjoys cooking.

UPDATED:  June 28, 2017